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priyankanandula
priyankanandula

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Create REST CRUD API With SpringBoot & SpringData-JPA.

#beginners #springboot #microservices #restapi

Signed in as @priyankanandula

Hurrah 😃 , finally I started writing technical blogs to share my practical implementation knowledge in programming.
This is the My First Blog come let's start 😍.

Hope you guys will definitely gain some knowledge after completion of reading this blog.

No delay let's start this 👇

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In this blog, you will learn how to develop RESTful web services APIs for CRUD operations on a MySQL database. The CRUD operations include Create, Retrieve, Update and Delete.

Technologies & Tools Required.

  • Java Development Kit (JDK 1.8 or newer)
  • MySQL Database server (including MySQL Workbench and MySQL Command Line Client to manage database)
  • STS(Spring Tool Suite)--4.10.0.RELEASE for creating SpringBoot projects  
  • Postman (to test RESTful APIs)

--

NOTE: You can use your favorite IDE like Eclipse, IntelliJ...

Implementation Steps :

  1. Creating SpringBoot Maven Project in STS.

  2. Creating Database in Mysql in CommandLine

  3. Creating a Table in Database using MySQL WorkBench UI.

  4. Creating an Entity Class in Project

  5. Creating a JPA Repository to perform CRUD Operations for Entity Class

  6. Configure Data Source Properties

  7. Creating a RestController Class for GET , POST, PUT ,UPDATE & DELETE HTTP Methods

  8. Run our SpringBoot Application in Embedded Tomcat Server

  9. Test our Restful services using Postman

We will create Final Project Structure as below
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1. Creating SpringBoot Maven Project in STS :

After open STS you can go through File ->New -> Spring Starter Project

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Provide the details as below:

1.Name - any name as your wish (in this blog I gave as ProductRestAPI)

2.Type - Maven

3.Group, Artifact & Package - you can give any values as your wish.

Here I have used...
  Group - com.priya.springweb
  Artifact - ProductRestAPI
  Package - com.priya.springweb

image

Click Next and then select the following dependencies that are required and then click finish.

1.The artifact spring-boot-starter-web is for Spring Web MVC, RESTful web services, and embedded Tomcat server.

2.The artifact spring-boot-starter-data-JPA is for Spring Data JPA and Hibernate.

  1. The artifact MySQL-connector-java is for the JDBC driver for MySQL.

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After click finish, the project gets created as below.

image

Maven POM File: 

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.priya.springweb</groupId>
    <artifactId>ProductRestAPI</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ProductRestAPI</name>
    <description>Demo project for Spring BootRestAPI</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>
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2.Creating Database in Mysql in CommandLine

Open MySQL Commandlind Client and log in with the password you have given at the time of installation.

I have used root user.

Create a database with any name in this I have used myproducts.

image

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3.Creating a Table in Database using MySQL WorkBench

Execute the following SQL script in WorkBench.

use myproducts;

create table product(
id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
name varchar(20),
description varchar(100),
price int
);
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image

4.Creating an Entity Class in Project

Create a package like com.priya.springweb.entities and then create the Product class to map with the product table in the database as follows:

package com.priya.springweb.entities;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class Product {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private int id;
    private String name;
    private String description;
    private int price;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    public int getPrice() {
        return price;
    }
    public void setPrice(int price) {
        this.price = price;
    }

}
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We have used @GeneratedValue(strategy=GenerationType.IDENTITY) because in the Database table we mentioned the id column as Auto_Increment to get these auto-generated values from a database.

NOTE: This is a simple domain model class, with class name and field names are identical to table name and column names in the database – so we can use the minimum number of JPA annotations.

5.Creating a JPA Repository to perform CRUD Operations for Entity Class

To take advantages of Spring Data JPA, create the ProductRepository interface as below:

package com.priya.springweb.repos;

import org.springframework.data.jpa.repository.JpaRepository;

import com.priya.springweb.entities.Product;

public interface ProductRepository extends JpaRepository<Product, Integer> {

}
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NOTE : Here JpaRepository arguments represents

6.Configure Data Source Properties

In main/resources/application. properties file we need to specify database-connection information as follows.

spring.datasource.url=jdbc:mysql://localhost:3306/myproducts
spring.datasource.username=root
spring.datasource.password=root

server.servlet.context-path=/productapi
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Remember to update url, username and password according to your MySQL database server.

NOTE:Here the context path is the name of the URL at which we access the application. The default context path is empty.you can provide any name here.

7.7.Creating a RestController Class for GET , POST, PUT ,UPDATE & DELETE HTTP Methods

Here, we come to the part that actually exposes RESTful APIs for CRUD operations – a Spring controller following REST style. Create the ProductController class with some initial code as below:

package com.priya.springweb.controllers;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.priya.springweb.entities.Product;
import com.priya.springweb.repos.ProductRepository;

@RestController
public class ProductController {

    @Autowired
    private ProductRepository repository;

    @RequestMapping(value="/products",method=RequestMethod.GET)
    public List<Product> getProducts(){

        return repository.findAll();
    }

    @RequestMapping(value="/products/{id}",method=RequestMethod.GET)
    public Product getProductById(@PathVariable("id") int id) {

        return repository.findById(id).get();

    }

    @RequestMapping(value="/products/",method=RequestMethod.POST)
    public Product createProduct(@RequestBody Product product) {

        return repository.save(product);
    }


    @RequestMapping(value="/products/",method=RequestMethod.PUT)
    public Product updateProduct(@RequestBody Product product) {

        return repository.save(product);

    }

    @RequestMapping(value="/products/{id}",method=RequestMethod.DELETE)
    public void  deleteProduct(@PathVariable("id") int id) {

    repository.deleteById(id);

    }
}
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 **@RestController** - The _@RestController_ annotation is used to define the RESTful web services. It serves JSON, XML and custom response
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@RequestMapping - The @RequestMapping annotation is used to define the Request URI to access the REST Endpoints. We can define Request method to consume and produce object. The default request method is GET.

@PathVariable - The @PathVariable annotation is used to define the custom or dynamic request URI. The Path variable in request URI is defined as curly braces {}

@RequestBody - The @RequestBody annotation is used to define the request body content type.

NOTE:You must use @ResponseBody for Update and Create operations.

8. Run the SpringBoot Application in Embedded Tomcat Server

Right Click on your project and then select run as Spring boot app.

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9. Testing our Restful services in Postman

1. Create Product Details - POST METHOD

URL : http://localhost:8080/productapi/products/

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NOTE : Here in body JSON no need to pass id as it as already automatically generated by Database.

Must Select data type as JSON .

image

Yo 🤘! Data inserted successfully. Great Job.

2.Get Product Details - GET METHOD

URL - http://localhost:8080/productapi/products

Response : 
[
    {
        "id": 1,
        "name": "IPhone",
        "description": "Its Awesome Product",
        "price": 1000
    },
    {
        "id": 2,
        "name": "Mac Book Pro",
        "description": "Its Amazing Product",
        "price": 3000
    },
    {
        "id": 6,
        "name": "Ipad Airpods",
        "description": "It is Good  Product",
        "price": 10000
    },
    {
        "id": 7,
        "name": "Ipad Mini",
        "description": "It is Good  Product",
        "price": 7000
    }
]
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NOTE : No need to pass any body for GET.

image

3. Get Product Details by ID - GET METHOD

URL - http://localhost:8080/productapi/products/7

Give any id of product that exists in Database Product table.

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4.Update Product Details - PUT METHOD

URL - http://localhost:8080/productapi/products/

{
    "id": 7,
    "name": "Ipad Mini",
    "description": "It is Good  Product",
    "price": 10000
}
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Here I am updating the price to 10000 earlier we have given 7000.

NOTE : You must mention all the fields for PUT Method based upon the Id it wil lupdate the details in database table

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5. 5.Delete Product Details by Id - DELETE METHOD

URL - http://localhost:8080/productapi/products/7

image

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It deleted the Product successfully .

Thats it guys,WOW 😀 Good Job .We have completed creating REST API CRUD in Spring Boot.

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Refer GIT Repository Details :

[Link] https://github.com/priyankanandula/SpringBoot-REST-API-CRUD

In next blog I will explain how to Consume these REST APIS using RestTemplate inside the code.

Have a Good Day, this is priyanka nandula signing off...

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